Abstract

Horizontal wells have been widely employed around the world to optimally depleted oil reservoir. As compared to a vertical well, however, drilling and completing a horizontal well is still more expensive. A production predictive tool is therefore needed to support its economic evaluation prior to implementation.

This paper presents a new method for horizontal-well coning prediction. This effort is made by considering that the available published correlations are based on a uniform flux model, which may not be the case for most field conditions as the reservoir flow geometry is affected by wellbore hydraulics. In the present study, one-dimensional displacement governing equation is used to develop the correlation. To account for both non-uniform flux and flow geometry, a dimensionless term derived from production history matching of a well case is introduced. This term accounts for drainage area, well length and well position with respect to the water/oil contact.

The method proposed is to forecast oil production and water cut versus producing time. These are vital for an economic evaluation and designing the capacity of water handling fasilities. The applicability of the method is demonstrated by example applications using two other sets of real field data.

Results of prediction and the production data are in very good agreement for the two cases. The sensitivity study performed herein suggests that permeability characteristics and withdrawal rate are most influential on production performance of a horizontal well producing oil from a bottomwater drive reservoir.